<!DOCTYPE html>
<div id="target">Test.</div>
<script>
if (window.testRunner)
  testRunner.waitUntilDone();

function waitForCompositor() {
  return document.body.animate({opacity: [1, 1]}, 1).finished;
}

target.animate({translate: '100px'}, 1e8);

requestAnimationFrame(() => {
  requestAnimationFrame(() => {
    target.style.translate = '100px';
    requestAnimationFrame(() => {
      waitForCompositor().then(() => {
        if (window.testRunner)
          testRunner.notifyDone();
      });
    });
  });
});
</script>
